1. Technical Field
The present invention relates to a switch device provided with a waterproof structure that prevents water from invasion from outside.
2. Related Art
An automobile includes an automatic window switch in order to perform opening and closing control of a window. Generally the automatic window switch includes an operation knob that is manually operated, a case that swingably supports the operation knob, and a circuit board that is accommodated in the case. The case includes an upper case and a lower case. An operation part is provided on an upper side of the upper case, and a lower side of the upper case is opened. The lower case is fitted in the upper case so as to close the lower side of the upper case. A contact part that switches in response to the operation of the operation knob and an electronic component constituting an electric circuit are provided on the circuit board.
In the automatic window switch, sometimes rainwater invading through an opened window or spilled beverages (hereinafter collectively referred to as “water”) invade into the case. The water invading into the case adheres to the circuit board to generate shortcircuit of the electric circuit or corrosion of the contact part, which causes a malfunction of the switch. Particularly, in the case that a hollow tube that swingably supports the operation knob is provided in an upper surface of the case, unfortunately the flowing-down water invades into the case from an upper opening of the tube through a gap between the operation knob and the tube.
Japanese Unexamined Patent Publication Nos. 11-86662 and 2006-221929 disclose structures, which prevent shortcircuit or contact corrosion from the invading water in the switch device in which the hollow tube supporting the operation knob is provided in the upper surface of the case.
In the switch device of Japanese Unexamined Patent Publication No. 11-86662, a rubber contact member is stacked on a circuit board, to which a terminal of a component is connected by soldering, so as to surround the soldered portion, and the rubber contact member is sandwiched between the circuit board and a switch body, thereby taking a waterproof measure.
In the switch device of Japanese Unexamined Patent Publication No. 2006-221929, a projection that blocks the invasion of water is provided in an outer side surface of the tube opposed to an inner side surface of the operation knob or the inner side surface of the operation knob opposed to the outer side surface of the tube. Additionally, plural grooves that block the invasion of water are vertically provided in the outer side surface of the tube opposed to the inner side surface of the operation knob.